1. Field
The disclosure generally relates to method and apparatus for low power NFC communication. More specifically, the disclosure relates to dynamic field control method to save energy and significantly reduce battery consumption during NFC real time communication between NFC devices.
2. Description of Related Art
Near field communication (NFC) is directed to technology that enables smart devices and other devices to establish radio communication with each other by touching the devices together or bringing them into proximity to a distance of typically 10 cm (3.9 in) or less. Early NFC business models were unsuccessful as they were overtaken by alternative technologies such as barcodes or UHF tags. Unlike barcodes and UHF tags, however, NFC devices are often cloud connected. All NFC-enabled smartphones can be provided with dedicated apps including so-called ticket readers as opposed to the traditional dedicated infrastructure that specifies a particular (often proprietary) standard for stock ticket, access control and payment readers.
NFC devices use electromagnetic induction between two loop antennae (i.e., RF field) when NFC devices (e.g., a smartphone and a smart-poster) come close to each other to exchange information. NFC sessions operate within the globally available unlicensed radio frequency Industrial, Scientific and Medical (ISM) radio band of 13.56 MHz on ISO/IEC 18000-3 air interface and support different data transmission rates.
Once a conventional NFC device (initiator) detects another NFC device (target) within its NFC RF field, Initial Detection phases (i.e., technology detection, Collision resolution phase; Activation phase) are triggered. Applications data can then be exchanged between the two NFC devices after the initial Detection phase. Thereafter, the initiator device must maintain its RF field ON regardless of whether there is application data to exchange between the initiator and target devices. The conventional NFC system has to maintain the RF field ON even when no upper layer application data is to be exchanged. That is, only when an NFC target is removed the conventional NFC field is disabled. As long as the two devices are close, NFC field is enabled even if there is no data need to be exchanged. The conventional NFC devices are inefficient.